In how many zones has the Indian Railways system been divided?

17

The correct answer is option 4: 17

NCERT: "Indian Railways is the largest government undertaking in the country. The length of Indian Railways network was 67,956 km (Railway yearbook 2019-20). Its very large size puts a lot of pressure on a centralised railway management system. Thus, in India, the railway system has been divided into 17 zones."